Silicon carbide films are often used as barrier layers in semiconductor substrate processing operations. As such, the silicon carbide film often must have a high density (e.g., more than about 2 g/cc), must be hermetic, and must have a low porosity to prevent diffusion of undesirable material through the barrier layer (e.g., metal atoms or air) or to prevent undesirable etching of the barrier layer.
Some have suggested that generating a remote hydrogen plasma may improve silicon carbide film properties. However, wall collisions and other quenching events are expected to reduce the yield of active species generated by a remote plasma. In turn, the film deposition rate for a remote hydrogen plasma process is expected to be unacceptably low. Because silicon carbide film density is believed to vary inversely with process pressure, increases in process pressure intended to increase deposition rate may adversely lower film density, leading to unacceptable barrier performance properties.